The present invention relates to a utilization technique of waste heat of a semiconductor fabrication apparatus, and more particularly to system and method for utilization of waste heat that reutilize heat of cooling water drained from a semiconductor fabrication apparatus as a heat source of another semiconductor fabrication apparatus, and a heat exchanger used in the system for utilization of waste heat.
A semiconductor fabrication facility includes a variety of semiconductor fabrication apparatuses used in semiconductor fabrication steps. In general, these semiconductor fabrication apparatuses are accommodated in a clean room. Accordingly, when heat is released from a semiconductor fabrication apparatus to its surrounding area, there occurs a temperature increase within the clean room. For this reason, cooling water is supplied to each semiconductor fabrication apparatus so as to prevent heat release to atmosphere in the clean room.
Among such semiconductor fabrication apparatuses, there is a heat processing apparatus, which has a heating furnace to process a semiconductor wafer at a high temperature (about 1000xc2x0 C.). Since a large amount of heat is released from a heating furnace to its surrounding area, cooling water is used to cool the surrounding area by absorbing the heat. Accordingly, a large amount of cooling water (for example, which has a temperature of 23xc2x0 C.) is supplied to a heat processing apparatus including a heating furnace under control of the cooling water so that the temperature of the cooling water drained from the heat processing apparatus can be about 30xc2x0 C.
Among the semiconductor fabrication apparatuses, there is also an apparatus having a heat source for heat processing. For instance, a wafer cleaning apparatus serves to clean a wafer by using deionized water (DIW) heated to 60xc2x0 C. through 80xc2x0 C., and contains a heat source to heat the deionized water. Namely, before deionized water of a room temperature (for example, 23xc2x0 C.) is supplied to the wafer cleaning apparatus to clean a wafer, the deionized water is heated to 60xc2x0 C. through 80xc2x0 C. by an electronic heater and so on.
As mentioned above, a large amount of heat is released to the exterior of a semiconductor fabrication facility via cooling water drained from the heat processing apparatus. In order to supply cooling water to a heat processing apparatus, power for circulating the cooling water and energy for cooling the heated cooling water again are required.
On the other hand, a wafer cleaning apparatus needs a large amount of heat for heating deionized water. Since an electronic heater is used to heat the deionized water, it is necessary to supply a large amount of electric power to the wafer cleaning apparatus.
In the semiconductor fabrication facility, a large amount of energy is consumed for cooling of a heat processing apparatus and heating of a wafer cleaning apparatus. From the viewpoint of energy saving, therefore, the semiconductor fabrication facility is wasteful in that energy is consumed for the cooling and the heating separately.
It is an object of the present invention to provide improved and useful system and method for utilization of waste heat in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide system and method for utilization of waste heat that can reduce an amount of total energy consumption of a semiconductor fabrication facility by using cooling water drained from a semiconductor fabrication apparatus as a heat source of another semiconductor fabrication apparatus, and a heat exchanger for such a system for utilization of waste heat.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a system for utilization of waste heat of a semiconductor fabrication apparatus, including: a heat processing apparatus being cooled by cooling water; a cleaning apparatus performing a cleaning process by using heated deionized water; a deionized water heating apparatus heating the deionized water used by the cleaning apparatus; a cooling water supply line supplying cooling water to the heat processing apparatus; a cooling water reutilization line supplying cooling water drained from the heat processing apparatus to the deionized water heating apparatus; and a cooling water recovery line recovering cooling water drained from the deionized water heating apparatus, wherein the deionized water heating apparatus heats deionized water through heat exchange with the cooling water supplied from the cooling water reutilization line.
The above-mentioned system may further include a cooling water circulation line coupling between the cooling water supply line and the cooling water recovery line. In addition, the system may further include circulation stop means for stopping flow of cooling water toward the cooling water circulation line when a temperature of the cooling water in the cooling water recovery line exceeds a predetermined temperature. In addition, in the above-mentioned system, the circulation stop means may include: a first switching valve being provided along the cooling water recovery line; a second switching valve being provided along the cooling water circulation line; and a temperature sensor detecting a temperature of cooling water in the cooling water supply line, wherein the first switching valve may be opened and the second switching valve may be closed when the temperature of the cooling water detected by the temperature sensor exceeds the predetermined temperature. In addition, in the above-mentioned system, the deionized water heating apparatus may include a contact portion with deionized water, the contact portion being formed of one of quartz glass and fluorosis resin.
Additionally, there is provided according to another aspect of the present invention a method for utilization of waste heat in a semiconductor fabrication facility having a heat processing apparatus and a cleaning apparatus, the method including the steps of: supplying to a deionized water heating apparatus cooling water drained from the heat processing apparatus after cooling for the heat processing apparatus; supplying deionized water to the deionized water heating apparatus, heating the deionized water through heat exchange with the cooling water, and supplying the heated deionized water to the cleaning apparatus; and recovering the cooling water drained from the deionized water heating apparatus.
The above-mentioned method may further include the step of supplying the cooling water drained from the deionized water heating apparatus to the heat processing apparatus directly. In addition, the method may further include the step of stopping supplying the cooling water drained from the deionized water heating apparatus to the heat processing apparatus when a temperature of the cooling water drained from the deionized water heating apparatus exceeds a predetermined temperature.
According to the above-mentioned inventions, cooling water (warm cooling water) heated by a heat processing apparatus and drained therefrom is supplied to a deionized water heating apparatus. The deionized water heating apparatus, which is a heat exchanger, heats deionized water of a low temperature (room temperature) through heat exchange with the warm cooling water drained from the heat processing apparatus and then supplies the heated deionized water to a cleaning apparatus. As a result, it is possible to heat the deionized water, which is conventionally heated by an electronic heater or the like, by using heat of the warm cooling water. Therefore, it is possible to reutilize heat from the heat processing apparatus, which is conventionally discarded via cooling water, as a heat source for the deionized water.
Additionally, there is provided according to another aspect of the present invention a heat exchanger for heating deionized water supplied to a semiconductor fabrication apparatus, including: a cooling water channel where warm cooling water, that is, heated cooling water, is supplied; and a deionized water channel where deionized water is supplied, the deionized water channel being formed of one of quartz glass and fluorosis resin, wherein heat is exchanged between the warm cooling water in the cooling water channel and the deionized water in the deionized water channel.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.